Use of thrombolytic reagents for prevention of vascular disease

ABSTRACT

The present invention relates to the administration of thrombolytic reagents such as tissue plasminogen activator (t-PA), streptokinase and/or urokinase, over prolonged periods of time for prevention of vascular disease such as cerebral vascular thrombosis, pulmonary embolism, deep venous thrombus, acute myocardial infarction and fresh or aged arterial thrombi. The invention relates generally to delivery systems that provide for sustained release of thrombolytic reagents such as tissue plasminogen activator (t-PA), streptokinase and/or urokinase, over prolonged periods of time. The thrombolytic reagents may be administered, for example, transdermally, topically, intranasally or orally.

INTRODUCTION

The present invention relates to the administration of thrombolyticreagents such as tissue plasminogen activator (t-PA), streptokinaseand/or urokinase, over prolonged periods of time for prevention ofvascular disease such as cerebral vascular thrombosis, pulmonaryembolism, deep venous thrombus, acute myocardial infarction and fresh oraged arterial thrombi. The invention relates generally to deliverysystems that provide for sustained release of thrombolytic reagents suchas tissue plasminogen activator (t-PA), streptokinase and/or urokinase,over prolonged periods of time. The thrombolytic reagents may beadministered, for example, transdermally, topically, intranasally ororally.

BACKGROUND OF THE INVENTION

TISSUE PLASMINOGEN ACTIVATOR

Thrombolytic drugs act on the endogenous fibrinolytic system byconverting plasminogen to the potent proteolytic enzyme plasmin. Plasminin turn degrades fibrin clots and other plasma proteins. A number ofthrombolytic drugs, including urokinase, streptokinase and t-PA, arecurrently used to treat acute vascular disease.

Tissue plasminogen activator (t-PA) activates plasminogen to generatethe proteinase plasmin which plays an important role in the degradationof fibrin. t-PA has been a particularly important pharmaceutical agentfor use in treatment of vascular diseases due to its ability to dissolveblood clots in vivo. t-PA was originally identified and purified fromnatural sources. Through the use of recombinant DNA techniques, DNAclones encoding the t-PA molecule have recently been identified andcharacterized leading to a determination of the DNA sequence and deducedamino acid sequence of t-PA (U.S. Pat. No. 4,853,330).

Several variants of t-PA have also been developed that address some ofthe disadvantages associated with the use of t-PA. These disadvantagesinclude the short half life and fast clearance rate of t-PA. Suchvariants include those described in EPO Patent Publication No. 199,574,that have amino acid substitutions at the proteolytic cleavage sites atamino acid positions 275, 276 and 277. These forms are referred to asprotease-resistant one-chain t-PA variants in that, unlike natural t-PA,they exist in either one chain or two chain form, are resistant toproteolytic cleavage and exist in one-chain form. Such variants arethought to be superior to natural t-PA for pharmaceutical uses in thatthey are more stable. In addition, a variety of glycosylation mutantsexist at positions 117, 119, 184-186 and 448-450 which exhibit higherspecific activity than natural t-PA.

A general review of plasminogen activators and derivatives thereof canbe found in Harris (1987, Protein Engineering 1:449-458); Pannekock etal. (1988, Fibrinolysis 2:123-132); and Ross et al. (1988, AnnualReports in Medicinal Chemistry, Vol. 23, Chapter 12), each of which isincorporated by reference herein.

VASCULAR DISEASE

Thrombosis and its complications are considered the most frequent causesof morbidity and death in the adult population. Pulmonary embolism isestimated to be the third most common cause of death in the UnitedStates (Mohr et al., 1988, Mayo Clin. Proc. 63:281-290). At present,anticoagulation is the basic approach to treatment of thromboembolicdisorders (Bick, R. et al., 1995, Laboratory Medicine 26:330-337;Shabahang, M. et al., 1994, Angiology 45:749-754). Pharmaceuticalpreparations containing thrombolytic reagents such as t-PA, urokinaseand streptokinase are currently used for treatment of acute vasculardisease.

Short term administration of pharmaceutical preparations containingthrombolytic reagents, such as t-PA, urokinase or streptokinase, arecurrently used to treat patients suffering from cardiovascular diseasesor conditions. For example, t-PA is parentally administered to patientsas a means for treatment of deep vein thrombosis or peripheral vasculardisease. t-PA is also used in connection with emergency medical carefacilities for treatment of arterial embolisms which include pulmonaryand extremity embolisms and infarction.

The deposition of fibrin in the peritoneal cavity may lead to fibrousadhesion formation which are the most common cause of small bowelobstruction in developed countries (Vipond et al., 1994, Ann. R. Coll.Surg. Engl. 76:412-415; EP 0297860 B1). t-PA has also been usedsuccessfully to prevent fibrin deposition or adhesion formation in theperitoneal cavity following surgery, infection, trauma or inflammation.

SUMMARY OF THE INVENTION

The present invention relates to methods for preventing vascular diseaseby the chronic administration of low doses of thrombolytic reagents suchas tissue plasminogen activator (t-PA), streptokinase and/or urokinase,over prolonged periods of time. The present invention also relates todelivery systems that can be used in the methods of the invention. Forexample, systems that provide for sustained release of thrombolyticreagents, such as t-PA, over prolonged periods of time can be used. Ingeneral, the total daily dose range of t-PA should be sufficient toachieve serum concentrations of between about 1 and 50 mgs. For example,between about 1 and 50 mgs of a daily parenteral dose may beadministered, most preferably a daily dose range should be between 10and 30 mgs of t-PA. Therefore, an object of the invention is to providedose-controlling applicators for thrombolytic compositions such as t-PA.

The present invention may be used therapeutically as a prophylacticmeans for inhibiting the development of vascular diseases such aspulmonary embolus, deep venous thrombus, acute myocardial infarction andfresh or aged arterial thrombi. The invention is of particular use fortreatment of individuals at high risk for vascular disease, such as,diabetics, hypertensive or hyperlipidemia patients, smokers or thoseindividuals with a family history of vascular disease.

The present invention encompasses a number of preferred embodiments. Inthe first, the thrombolytic reagent is contained in a dermal patch whichmay be used to provide sustained release of tissue plasminogen activatorinto a patient's bloodstream over prolonged periods of time. In anotherembodiment of the invention the thrombolytic reagent may be combinedwith slow release gel formulations which may be applied topically to thepatient. In yet another embodiment of the invention the thrombolyticreagent may be added to a biocompatible matrix material which may beimplanted into the body of the patient for slow sustained release of thereagent. The thrombolytic reagent may also be administered orally orintranasally through the use of nasal sprays containing the reagent.

DETAILED DESCRIPTION OF THE INVENTION

Thrombosis and its complications are considered the most frequent causesof morbidity and death in the adult population. The present inventioninvolves a prophylactic method for inhibiting the development ofvascular disease such as pulmonary embolus, deep venous thrombus andacute myocardial infarction and cerebral vascular thrombus. Theinvention relates to the chronic administration of low doses ofthrombolytic reagents to prevent vascular disease. The thrombolyticreagents may be administered daily, weekly, monthly or yearly dependingon the type of delivery system utilized. The desired goal of any suchdelivery systems is a constant long term delivery of thrombolyticreagents. Such thrombolytic reagents include, for example, t-PA,streptokinase and urokinase, etc.

The invention is of particular use for treatment of individuals at highrisk for vascular disease, such as, diabetics, hypertensive orhyperlipidemia patients, smokers or those individuals with a familyhistory of vascular disease. In such patients, the delivery of acontinuous sustained release of thrombolytic reagents, such as t-PA,streptokinase or urokinase, may prevent the development of vasculardisease.

Thus, the present invention relates to the chronic administration of lowdoses of thrombolytic reagents such as tissue plasminogen activator,streptokinase and/or urokinase over prolonged periods of time forprevention of vascular disease. The invention further relates todelivery systems that provide for long-term sustained release ofthrombolytic reagents, such as t-PA, in the blood, which is effective asa means for preventing the development of vascular disease. The objectof the invention is the prevention or dissolving of clots as they formin the vascular system of the treated patient. In accordance with thepresent invention, the object can be achieved through the use of t-PApreparations designed for sustained release of t-PA into the bloodstreamof a patient over prolonged periods of time.

THROMBOLYTIC REAGENTS

The thrombolytic reagents to be used in the practice of the invention,herein defined as any reagents which have fibrinolytic activity, may bederived from a variety of different sources. For example, the t-PA maybe produced in large quantities using recombinant DNA techniques wellknown to those skilled in the art such as those disclosed in U.S. Pat.No. 4,853,330 which is incorporated herein by reference. Alternatively,the t-PA may be obtained from a number of commercially available sourcessuch as Activase© supplied by Genentech, Inc.

When using t-PA, it is within the scope of the invention that variantsof naturally occurring t-PA may also be used in the practice of theinvention. In preferred embodiments, such variants of t-PA may have anincreased half life or a slower rate of clearance from the body. Forexample, variants having amino acid substitutions at the proteolyticcleavage sites at position 275, 276 and 277 which render t-PApreparations more stable may be used. Glycosylation mutants at aminoacids 117-119, 184-186 and 448-45 exhibit a higher specific activity andsuch variant may also be used in the practice of the invention. t-PA canalso be modified to delete amino acids 51-87 which results in a varianthaving a slower clearance from plasma. These variants represent only asubset of the known variants of t-PA which may be used in the presentlyclaimed delivery systems.

It is also within the scope of the present invention that thrombolyticreagents other than t-PA may be used in the practice of the invention.Such agents include urokinase and streptokinase both of which may beobtained from commercial sources (Urokinase, Abbott Laboratories;Streptokinase, Pharmacia Adria).

METHOD OF PREVENTING VASCULAR DISEASE

The present invention relates to methods of preventing vascular diseaseby chronic administration of low doses of thrombolytic reagents. Thepresent invention may be used as a prophylactic means for inhibiting thedevelopment of vascular diseases such as cerebral vascular thrombosis,pulmonary embolus, deep venus thrombus and acute myocardial infarction.The invention is of particular use for treatment of individuals at highrisk for vascular diseases.

Pharmaceutical compositions suitable for use in the present inventioninclude compositions wherein the thrombolytic ingredients are containedin an effective amount to achieve its intended purpose. Morespecifically, a therapeutically effective amount means an amounteffective to prevent development of vascular disease in the subjectbeing treated. A therapeutically effective dose refers to that amount ofthe compound that results in plasma levels of the thrombolytic reagentwhich are sufficient to maintain the beneficial modulating effects.Determination of the effective amounts is well within the capability ofthose skilled in the art.

The effective dose may be determined using a variety of differentassays. For example, assays may be utilized to determine levels offibrinogen or fibrin split products in the blood of treated patients. Insuch instances, the effective dose of the thrombolytic reagent is thatamount required to sustain normal levels of fibrinogen or fibrin splitproducts in the body of the patient. Such doses may be determined bymeasuring for levels of fibrinogen (assay for measuring levels offibrinogen is available from M.L.A.,Inc.) or fibrin split products(Thrombo-Wellco Test;MUREX, Inc.) in the blood of treated patients. Atherapeutically effective dose refers to that amount of thrombolyticreagent sufficient to maintain normal circulating blood levels of about2-4 mg/ml of fibrinogen, or, less than 10 mg/ml of fibrin splitproducts.

The amount of composition administered will, of course, be dependent onthe subject being treated, on the subject's weight, the severity of theaffliction, the manner of administration and the judgment of theprescribing physician. It should be noted that the attending physicianwould know how to and when to terminate, interrupt or adjust therapy tolower dosage due to toxicity. Conversely, the attending physician wouldalso know to adjust treatment to higher levels if the clinical responseis not adequate (precluding toxicity).

In administering thrombolytic reagents to the patient, it isparticularly important to monitor the patient for excessive bleeding ortendencies to bleed. A variety of different diagnostic tests, which arewell known to those skilled in the art may be used to access thepatients susceptibility to bleeding due to administration of thethrombolytic reagents. Such assays include a complete blood count (CBC),or a determination of prothrombin or partial prothrombin time.

The magnitude of a prophylactic dose of the t-PA in the management ofvascular disease will vary with the patient to be treated and the routeof administration. Again, it should be noted that the clinician orphysician would know when to interrupt and/or adjust the treatment dosedue to toxicity. The dose, and perhaps the dosage frequency, will alsovary according to the age, body weight, and response of the individualpatient.

In general, the total daily dose range of t-PA should be sufficient toachieve serum concentration levels ranging between 1 and 50 mgs. Forexample, between about 1 and 50 mgs of a daily parenteral dose may beadministered, while most preferably a daily dose range should be betweenabout 10 and 30 mgs of a parenteral dose of t-PA. For smaller patients(less than 65 kg), a dose of 0.1-0.5 mg/kg may be administered daily. Itis further recommended that infants, children, and patients over 65years, and those with impaired renal, or hepatic function, initiallyreceive low doses, and that they be titrated based on individualclinical response(s) and blood level(s). It may be necessary to usedosages outside these ranges in some cases as will be apparent to thoseof ordinary skill in the art.

THROMBOLYTIC DRUG DELIVERY SYSTEMS

A variety of drug delivery systems may be used to deliver thethrombolytic reagents, such as t-PA into the bloodstream of the patient.For example, the t-PA can be administered to a human patient inpharmaceutical compositions where it is mixed with suitable carriers orexcipient(s) at doses therapeutically effective to prevent a variety ofvascular disorders. Suitable routes of administration may, for example,include transdermal, topical, oral, intranasal and the like. Dosageforms include but are not limited to aerosol dispersions, creams,patches and the like.

For purposes of clarity, the following discussion describes deliverysystems for t-PA. However, the delivery systems are not so limited. Itis understood that the delivery systems described below may also beutilized for delivery of other thrombolytic reagents such as urokinaseand streptokinase. Techniques for formulation and administration of thethrombolytic reagents of the instant application may be found in"Remington's Pharmaceutical Sciences," Mack Publishing Co., Easton, Pa.,latest edition.

Pharmaceutical compositions for use in accordance with the presentinvention thus may be formulated in conventional manner using one ormore physiologically acceptable carriers comprising excipients andauxiliaries which facilitate processing of the t-PA into preparationswhich can be used pharmaceutically. Proper formulation is dependent uponthe route of administration chosen. Suitable routes of administrationmay, for example, include transdermal, topical, oral, intranasal and thelike. Dosage forms include but are not limited to aerosol dispersions,creams, patches and the like.

The formulations of the present invention normally will consist of t-PAwith a carrier, or diluted by a carrier. Some examples of the diluentsor carriers which may be employed in the pharmaceutical compositions ofthe present invention are lactose, dextrose, sucrose, sorbitol,mannitol, propylene glycol, liquid paraffin, white soft paraffin,kaolin, microcrystalline cellulose, calcium silicate, silicapolyvinylpyrrolidone, cetostearyl alcohol, starch, gum acacia, calciumphosphate, cocoa butter, oil of theobroma, arachis oil, alginates,tragacanth, gelatin, syrup B.P., methyl cellulose, polyoxyethylenesorbitan monolaurate, ethyl lactate and propylhydroxybenzoate, sorbitantrioleate, sorbitan sesquioleate and oleyl alcohol.

Because of the short shelf life of t-PA in solution, formulations oft-PA in aqueous solutions, gels, etc. are stored under refrigeration topreserve the activity of the t-PA. Lyophilized preparations of t-PA maybe stored at room temperature and protected from excessive exposure tolight without loss of activity.

A variety of different drug delivery systems may be used to deliver t-PAinto the bloodstream of the patient. In one particular embodiment of theinvention a dermal patch may be used for sustained delivery of t-PA intothe body. These membrane systems are designed to deliver controlleddoses of drugs through the skin into the bloodstream.

TRANSDERMAL DELIVERY SYSTEM

Transdermal delivery of t-PA can be designed so that the rate ofdelivery of the t-PA closely follows the rate of clearance of the t-PAfrom the patient's body, thus keeping constant levels of the t-PA in theblood, thereby reducing t-PA waste and overdosing. The use of such adrug delivery system also provides a comfortable, convenientnon-invasive method for unattended delivery of t-PA over a prolongedtime period.

The transdermal patches to be used in the practice of the invention maybe obtained from any of a variety of commercial sources. Most patchesconsists of a reservoir of drug material located behind a ratecontrolling membrane. The patch is impregnated with the t-PA and placedon the skin of the patient which allows the drug to penetrate readilyinto the body. In the practice of the invention the transdermal patchwill be periodically replaced as the t-PA becomes depleted.

The transdermal patch is prepared to contain a solution of t-PA. Thet-PA is dispersed in the solution, suspension or gel in a dissolved orundissolved state. The drug reservoir of the patch containing asolution, suspension or gel of t-PA also includes permeation enhancerswhich increase the skin penetration of the t-PA. Such permeationenhancers include those described in U.S. Pat. No. 4,573,966, which isincorporated by reference herein. Permeation enhancers may includeplasticizer type enhancers such as lower alky and alkoxy esters ofpharmaceutically acceptable fatty acids, fatty acid esters, fattyalcohols and similar hydrophobic compounds that are capable ofincreasing the permeability of drugs to the skin. In addition, solventtype enhancers may be used to increase the delivery of drugs through theskin. Such enhancers generally refer to relatively hydrophilic compoundshaving molecular weights of less than 200. More preferably, solvent typeenhancers have a molecular weight of less than 150. They are alsogenerally greater than 2 wt % soluble in water, and are preferablygreater than 10 wt % soluble in water. Typically, solvent type enhancersinclude pharmaceutically acceptable lower alkyl alcohol, aryl alcohol,or polyol, for example, ethanol, propanol, butanol, benzyl alcohol,glycerin, or propylene glycol. as well as diluents, such as water orother additives. The solution of t-PA may be formulated to includevascular permeability factors (VPFs), as described in U.S. Pat. No.5,503,843, which cause a rapid and reversible increase in blood vesselpermeability. Such VPF may be added to the t-PA solution to facilitatethe uptake of t-PA into the blood vessels of the skin. In addition,gelling agents may be added to increase the viscosity of the solution asis described in U.S. Pat. No. 5,503,843. The t-PA may also includediluents, stabilizers, biocides, antioxidants, anti-irritants and thelike.

Because of the instability of t-PA in solution, it is desirable todesign transdermal patches that can be stored at room temperature. Sucha dermal patch may be designed, for example, with two compartmentsseparated by a breakable barrier; one compartment contains lyophilizedt-PA and the other compartment contains a solution or carrier, such asthose described above, into which the t-PA is dissolved. Prior to theuse of the patch, the barrier is broken, mixing the contents of bothcompartments thereby forming a drug reservoir containing a solution oft-PA. Alternatively, a transdermal patch may be designed with a singlebreakable compartment containing lyophilized t-PA, enclosed within theliquid carrier. Prior to use of the patch, the single compartmentbarrier is broken releasing the lyophilized t-PA into the carriersolution. The patch is then placed in contact with the skin in such away that the drug reservoir containing the t-PA solution is in contactwith the skin.

INTRANASAL DELIVERY SYSTEM

In yet another embodiment of the invention, the t-PA may be administeredintranasally. The large blood supply carried in the capillaries of thenose allow drugs to enter the bloodstream quickly. For administration byinhalation, t-PA are conveniently delivered in the form of an aerosolspray presentation from pressurized packs or a nebulizer, with the useof a suitable propellant, e.g., dichlorodifluoromethane,trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide orother suitable gas. In the case of a pressurized aerosol the dosage unitmay be determined by providing a valve to deliver a metered amount.Capsules and cartridges of e.g., gelatin for use in an inhaler orinsufflator may be formulated containing a powder mix of the compoundand a suitable powder base such as lactose or starch.

In addition, the inhalers may be formulated to include vascularpermeability factors (VPFs) which cause an increase in blood vesselpermeability thereby facilitating the uptake of t-PA into the bloodvessels of the nose.

IMPLANTABLE DELIVERY SYSTEMS

In addition to the formulations described above, the t-PA may also beformulated as a slow release preparations that may be administered byimplantation (for example subcutaneously or intramuscularly) or byintramuscular injection. Thus, for example, the t-PA may be formulatedwith suitable biocompatible matrix materials. The compounds may bedelivered using a sustained-release system, such as slow release gelformations containing the t-PA. Various slow release gel formations havebeen established and are well known by those skilled in the art.Sustained-release capsules may, depending on their chemical nature,release the t-PA for prolonged periods of time.

ORAL FORMULATIONS

For oral administration, the compounds can be formulated readily bycombining the active compounds with pharmaceutically acceptable carrierswell known in the art. Such carriers enable the compounds of theinvention to be formulated as tablets, pills, dragees, capsules,liquids, gels, syrups, slurries, suspensions and the like, for oralingestion by a patient to be treated. Pharmaceutical preparations fororal use can be obtained solid excipient, optionally grinding aresulting mixture, and processing the mixture of granules, after addingsuitable auxiliaries, if desired, to obtain tablets or dragee cores.Suitable excipients are, in particular, fillers such as sugars,including lactose, sucrose, mannitol, or sorbitol; cellulosepreparations such as, for example, maize starch, wheat starch, ricestarch, potato starch, gelatin, gum tragacanth, methyl cellulose,hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and/orpolyvinylpyrrolidone (PVP). If desired, disintegrating agents may beadded, such as the cross-linked polyvinyl pyrrolidone, agar, or alginicaced or a salt thereof such as sodium alginate.

Dragee cores are provided with suitable coatings. For this purpose,concentrated sugar solutions may be used, which may optionally containgum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethyleneglycol, and/or titanium dioxide, lacquer solutions, and suitable organicsolvents or solvent mixtures.

The t-PA is preferably formulated for oral administration with entericcoatings which protect the t-PA from enzymatic degradation in thestomach and promotes uptake by the intestinal tract. Such formulationsare designed for slow release of t-PA through the intestinal wall andinto the bloodstream of the patient. For example, the drug capsulecontaining t-PA may be coated with an enteric film which is sufficientlyinsoluble at a pH below 7 as to be capable of protecting the capsule andits contents from the digestive enzymes until the capsule reaches aregion below the upper part of the intestine. Such film compositionsinclude mixtures of anionic acrylic copolymers derived from at least onmonomer selected from acrylic and methacrylic acids and methylacrylates.Such copolymers are commercially available under the trade name"Eudragit"(TM). Such enteric coatings are well known to those skilled inthe art, and include those described in U.S. Pat. No. 4910021 and U.S.Pat. No. 5350741, each of which is incorporated by reference herein.Dyestuffs or pigments may also be added to the tablets or drageecoatings for identification or to characterize different combinations ofactive compound doses.

Pharmaceutical preparations which can be used orally include push-fitcapsules made of gelatin, as well as soft, sealed capsules made ofgelatin and a plasticizer, such as glycerol or sorbitol. The push-fitcapsules can contain the active ingredients in a mixture with fillersuch as lactose, binders such as starches, and/or lubricants such astalc or magnesium stearate and, optionally, stabilizers. In softcapsules, the active compounds may be dissolved or suspended in suitableliquids, such as fatty oils, liquid paraffin, or liquid polyethyleneglycols. In addition, stabilizers may be added. All formulations fororal administration should be in dosages suitable for suchadministration.

For buccal administration, the compositions may take the form of tabletsor lozenges formulated in a conventional manner.

PARENTERAL FORMULATIONS

The compounds may be formulated for parenteral administration byinjection, e.g., by bolus injection or continuous infusion. Formulationsfor injection may be presented in unit dosage form, e.g., in ampoules orin multi-dose containers, with an added preservative. The compositionsmay take such forms as suspensions, solutions or emulsions in oily oraqueous vehicles, and may contain formulator agents such as suspending,stabilizing and/or dispersing agents.

Pharmaceutical formulations for parenteral administration includeaqueous solutions of the active compounds in water-soluble form.Additionally, suspensions of the active compounds may be prepared asappropriate oily injection suspensions. Suitable lipophilic solvents orvehicles include fatty oils such as sesame oil, or synthetic fatty acidesters, such as ethyl oleate or triglycerides, or liposomes. Aqueousinjection suspensions may contain substances which increase theviscosity of the suspension, such as sodium carboxymethyl cellulose,sorbitol, or dextran. Optionally, the suspension may also containsuitable stabilizers or agents which increase the solubility of thecompounds to allow for the preparation of highly concentrated solutions.

Alternatively, the active ingredient may be in powder form forconstitution with a suitable vehicle, e.g., sterile pyrogen-free water,before use.

The compounds may also be formulated in rectal compositions such assuppositories or retention enemas, e.g., containing conventionalsuppository bases such as cocoa butter or other glycerides.

PACKAGING

The compositions may, if desired, be presented in a pack or dispenserdevice which may contain one or more unit dosage forms containing theactive ingredient. The pack may for example comprise metal or plasticfoil, such as a blister pack. The pack or dispenser device may beaccompanied by instructions for administration. Compositions comprisinga compound of the invention formulated in a compatible pharmaceuticalcarrier may also be prepared, placed in an appropriate container, andlabelled for treatment of an indicated condition. Suitable conditionsindicated on the label may include treatment of patients at risk fordevelopment of vascular diseases, or alternatively treatment of patientssuffering from vascular diseases such as cerebral vascular thrombosis,pulmonary embolism, deep venous thrombos, acute myocardial infarctionand fresh or aged arterial thrombi.

EXAMPLE

TRANSDERMAL ADMINISTRATION OF THROMBOLYTIC REAGENTS

The following example describes the administration of the thrombolyticreagent t-PA utilizing a transdermal patch delivery system. The use oftransdermal patches for the delivery of drugs through the skin is wellknown. Methods for the use of transdermal patches for delivery of drugsis described, for example, in the following United States patents, U.SSer. Nos. 5,498,417, 5,503,844 and 5,503,843, each of which isincorporated by reference herein.

The following example illustrates the invention. It is not intended tolimit the scope of the invention.

The t-PA (Activase, supplied by GENENTECH, Inc.) to be used in thisexample is supplied in 50 mg vials. The vials should be reconstituted ineither sterile water or a pharmaceutical composition compatible with usein a transdermal patch.

The transdermal patch is prepared to contain a solution of t-PA. Thet-PA is dispersed in the solution, suspension or gel in a dissolved orundissolved state. The drug reservoir of the patch containing asolution, suspension or gel of t-PA also includes permeation enhancerswhich increase the skin penetration of the t-PA. Such permeationenhancers include those described in U.S. Pat. No. 4,573,966, which isincorporated by reference herein. Permeation enhancers may includeplasticizer type enhancers such as lower alky and alkoxy esters ofpharmaceutically acceptable fatty acids, fatty acid esters, fattyalcohols and similar hydrophobic compounds that are capable ofincreasing the permeability of drugs to the skin. In addition, solventtype enhancers may be used to increase the delivery of drugs through theskin. Such enhancers generally refer to relatively hydrophilic compoundshaving molecular weights of less than 200. More preferably, solvent typeenhancers have a molecular weight of less than 150. They are alsogenerally greater than 2 wt % soluble in water, and are preferablygreater than 10 wt % soluble in water. Typically, solvent type enhancersinclude pharmaceutically acceptable lower alkyl alcohol, aryl alcohol,or polyol, for example, ethanol, propanol, butanol, benzyl alcohol,glycerin, or propylene glycol. as well as diluents, such as water orother additives. The solution of t-PA may be formulated to includevascular permeability factors (VPFs), as described in U.S. Pat. No.5503843, which cause a rapid and reversible increase in blood vesselpermeability. Such VPF may be added to the t-PA solution to facilitatethe uptake of t-PA into the blood vessels of the skin.

The amount of t-PA contained in the patch is that amount necessary todeliver a daily dose of between 1-50 mg of t-PA. The treated patient'sblood is monitored to determine the levels of circulating fibrinogenand/or fibrin split products. The amount of t-PA contained in the patchis adjusted so as to maintain blood levels of about 2-4 mg/ml offibrinogen and 10 mg/ml of fibrin split products. In addition, thetreated patient is monitored to prevent excessive bleeding which canresult from treatment with thrombolytic reagents.

Once the transdermal patch has been prepared to contain an appropriatedose of t-PA, in a suitable solution, the patients skin is overlaid withthe transdermal patch. The patch is placed in contact with the skin insuch a way that the side of the patch containing the t-PA solution sideis in contact with the patient's skin.

The present invention is not to be limited in scope by the specificembodiments described which are intended as single illustrations ofindividual aspects of the invention, and functionally equivalent methodsand components are within the scope of the invention. Indeed, variousmodifications of the invention, in addition to those shown and describedherein will become apparent to those skilled in the art from theforegoing description and accompanying drawings. Such modifications areintended to fall within the scope of the claims.

What is claimed:
 1. A method for prevention of thrombotic vasculardisease in a mammal, comprising the chronic administration to a patientin need thereof of an effective dose of a thrombolytic reagent to amammal.
 2. The method of claim 1 wherein the thrombolytic reagent ishuman tissue plasminogen activator.
 3. The method of claim 1 wherein thethrombolytic reagent is streptokinase.
 4. The method of claim 1 whereinthe thrombolytic reagent is urokinase.
 5. The method of claim 1 whereinthe thrombolytic reagent is delivered in a transdermal patch.
 6. Themethod of claim 5 wherein the thrombolytic reagent is selected from thegroup consisting of human tissue plasminogen activator, streptokinaseand urokinase.
 7. The method of claim 2 wherein the human tissueplasminogen activator is recombinant human tissue plasminogen activator.8. The method of claim 1 wherein the thrombolytic reagent is deliveredinternasally.
 9. The method of claim 8 wherein the thrombolytic reagentis selected from the group consisting of human tissue plasminogenactivator, streptokinase and urokinase.
 10. The method of claim 1wherein the thrombolytic reagent is delivered topically in a topicalcream.
 11. The method of claim 10 wherein the thrombolytic reagent isselected from the group consisting of human tissue plasminogenactivator, streptokinase and urokinase.
 12. The method of claim 1wherein the thrombolytic reagent is delivered orally.
 13. The method ofclaim 12 wherein the thrombolytic reagent is selected from the groupconsisting of human tissue plasminogen activator, streptokinase andurokinase.
 14. The method of claim 1 wherein the dose of thethrombolytic reagent is that dose sufficient to maintain circulatingblood levels of 2-4 mg/ml of fibrinogen or less than 10 mg/ml of fibrinsplit products.
 15. The method of claim 1 wherein the dose of thethrombolytic reagent is that dose sufficient to maintain circulatingblood levels of less than 10 mg/ml of fibrin split products.
 16. Themethod of claim 2 wherein the daily dose of t-PA is between 1-50 mg. 17.The method of claim 2 wherein the daily dose of t-PA is between 10-30mg.